Internal-combustion engine



1944- GJR. ERIQCSON ET AL 2,355,716

INTERNAL-COMBUSTION ENGINE Filed May 16, 1940 INVENTORS GEORGE R.ERIC'SON IRVEN E. COFFEY h I I H ATTORNEY 1 Patented Aug. 15, 1944UNITED shares 4 PATENT orrica 2,355,716 INTERNAL-COMBUSTION ENGINEGeorge R. Ericson, Kirkwood, and Irven E. l Coley, Normandy, Mo.

Application May is, 1940. Serial No. 335,590 r intake manifold atcertain engine speeds cause faulty distribution of mixture both as tovolume and quality, so that when higher speeds are attained theadmission of mixture to the engine becomes restricted by the inertia ofgases movierent cylinders, as well as by the restriction presented bythe various passages of the carburetor.

Another difliculty that has been found in operating internal combustionengines over wide ranges of speeds and loadsis due to the limitations ofthrottle range or volume range in modern carburetors. For instance, aplain tube carburetor having a venturi of suflicient size and capacityto supply the fuel requirements of the engine under wide'open throttlehigh speed con-,

ditions fails to develop a substantial suction under low speed wide openthrottle conditions.

It is an object of this invention to produce a 'new and improvedcarburetion and manifolding system for internal combustion engines inwhich the advantages of the plain tube carburetor may be retained,without the disadvantage of having to make the choice between anextremely large ing in the wrong direction inthe intake manifold and byvariations in mixture quality between dif- 11 Claims. (Cl. 12'3-127) toone or more cylinders of an internal combustion engine. It will beunderstood that other cylinders may also be connected to the sameconduit at different points along the length thereof. The constructionand operation ofthese cylinders is well known and is not shown, but itwill be understood by those skilled in the art that the manifoldisconnected to the valve controlled inlet ports of a four cycleengineand this invention is especially adapted toengines in which theintake valve lags some forty degrees or more beyond the bottom deadcenter of the piston; that is to say, the intake valve is held open asubstantial length of time after the piston has begun its compressionstroke. While this lag is highly desirable for certain speed andoperating conditions, it creates such disturbances as pulsation in themanifold at certain operating speeds and as stated above, one of theobjects of the invention is to dampen these pulsations. The referencenumeral 6 indicates the main hot spot which is a heating jacket throughwhich exhaust gases may flow around the intake manifold, the flow beingcontrolled by a valve 1 which is operated venturi for maximum speedoperation and a smaller venturi for flexible iower speed operation. i

It. is a further. object of this invention to produce a carburetion andmanifolding system in which the pulsations resulting from back flow fromthe various cylinders under certain conditions will be damped so as toproduce a greater freedom of flow of mixture to the engine with I moreuniformity of quality and less restriction than has been previouslypossible.

Another object of this invention is to provide a new and improvedheating device for the fuel mixture. i

Other objects and advantages will appear from the following descriptionand accompanying drawing, referring to which the single figure is aschematic representation of a main carburetor and an auxiliarycarburetor mounted on associated intake and exhaust manifolds of. theensin'e.

by a thermostat 8. The specific construction of the thermostat may bechosen as desired, but in the construction shown the thermostat is ofthe type which is filled with an expansible fluid so as to push on thelink 8 when the heat exceeds a predetermined degree, thereby opening thevalve 1 to the position shown in solid lines in the drawing andpermitting the exhaust gases to flow out through the exhaust manifoldII] with .out necessarily flowing through the hotspot 6. The auxiliaryhot spot II is applied at the Junetion ofthe auxiliary carburetor I!with the intake manifold. The construction of the auxiliary hot spot IIand the auxiliary heat valve I 3 are the same as of the main hot spotand heat valve except that the auxiliary heat valve is controlled by a.connection. II with the operating lever l 5 of the auxiliary throttle[8.

The main carburetor I1 is of a well known plain tube type. While thiscarburetor is only diagrammatically shown, it may be said that it is aplain tube carburetor of thedown-draft triple venturi type having a mainnozzle l8 which may be of the general character shown in theBicknellPatent 1,848,615. The automatic choke is The reference numeral lindicates an intake..

conduit having a main inlet 2 and an auxiliary inlet 3 and havingoutlets '4 and I, each leading not shown but may be of the type shown inCoffey Patent 2,085,351 or Ericson 1,915,851. The idling I device isalso omitted from the drawing but a typical idle may be found in theErlcson- Patent 1,915,851. v This main carburetor may have one v or anynumber of. venturi tubes but in the pres quarter open throttle andthereby prevent the operation of the auxiliary carburetor when the maincarburetor is being operated at part throttle.

The auxiliary carburetor may be substantially the same in constructionas the main carburetor except for the operation of the throttle, I6. Theauxiliary throttle operating lever is provided with an arm 25 connectedby means of the link 26 to a piston 21 which is mountedin the cylinder28 and biased in throttle closing direction by a compression spring 29.The construction of this spring is of some importance as it is desiredto have a comparatively low rate of pressure build up from the closedthrottle position to the open throttle position. To this end a spring ofcomparatively great length and low strength is used and compressed toonly a fraction of its original length so that the rate of change perunit of movement of the piston is comparatively small. To the same endthe angle of the arm 25 with respect to the plain of the throttle platel6 and the position of the piston 21 is so arranged as to produce adecreasing ratio of valve movement as the valve is opened.

In the operation, the operator controls the manual throttle 23, andduring low speed and idling conditions the auxiliary throttle I6 issubstantially closed except for the idle passage which may be providedif desired. It will be understood of course that some slight opening ofthe throttle valve is may be provided for with the usual stop screw.Under low speed operating conditions even with the manual throttle 28wide open there will not be enough suction at the throat of thesecondary venturi .20 to act through the passage 2| and valve 2% to movethe piston 21 to the left against the vices may be-used. These, however,are preferably omitted from the auxiliary carburetor and used only inthe main carburetor as the speed of operation at which the auxiliarycarburetor comes in is such that no pick up device is necessary and theauxiliary carburetor is calibrated to deliver a power mixture only, sothat the I use of an economizer would be pointless.

manually operated throttle.

auxiliary throttle closing spring 29, but with the throttle 23 wideopen, or nearly so, suction in they secondary venturi will increase, asthe engine speed increases, to a point at which the throttle l8 will beopened by the suction.v This point is preferably at around 40 miles anhour in the operation of the average car, but may be higher if desired.Once the auxiliary carburetor throttle begins to open, further increasesin the speed of the automobile will cause it to open at a fairly rapidrate thereby increasing the rate of air admission to the manifold butwithout causing the manifold suction to fall below the point at whichthe spring 29 originally begins to yield.

The introduction of the auxiliary carburetor mixture at a pointsubstantially spaced along the manifold from the main carburetorsubstantially damps the'pulsations due to back pressure from thecylinders at the point in the cycle just prior to the closing of theintake valve and the eliminating resistance to flow as well as bydamping pulsations.

It will be understood that mixture controi devices of the type known asaccelerating pumps,

2. In an internal combustion engine having intake passagemeans, meansforming a plurality of mixing conduits for supplying fuel to saidpassage means, a manually operated throttle valve for one of saidconduits and an automatically operated throttle valve for the other ofsaid conduits, said automatic valve being controlled by suctiondeveloped at a point anterior to the manually operated throttle, andmeans controlled in accordance with the position of said manuallyoperated throttle for preventing the opening of said automatic throttleexcept when said manually operated throttle has been opened to apredetermined degree;

3. In an internal combustion engine, an intake manifold having aplurality of longitudinally spaced mixture inlets, a main mixing conduitconnected to oneoi said inlets and an auxiliary mixing conduit connectedto the auxiliary inlet and means controlled by the operator butdependent on the attainment of a predetermined rate of flow through saidmain conduit to said engine for opening said auxiliary conduit, thelongitudinal spacing of the mixture inlets being ample to permit themixture from the auxiliary inlet to damp the back pressure pulsations.

4. In an internal combustion engine, an intake manifold having aplurality of mixture inlets, a main mixing conduit connected to one ofsaid inlets and an auxiliary mixing conduit connected-to the otherinlet, a. manually operated throttle valve for said main mixing conduit,9. second valve for said auxiliary conduit, means normally holding saidsecond valve in substantially closed position, devices actuated, respectively, by said manual throttle and pressure changes in said main mixingconduit for controlling said second valve.

for said auxiliary mixing conduit and means pick up devices andeconomizers or step up ,de- 76 controlled by suction developed anteriorto the throttle in said main mixing conduit for controlling saidauxiliary valve.

6. In{ an internal combustion engine, an intake manifold having aplurality of mixture inlets, a main mixing conduit connected to one ofthrottle valve for said main mixing conduit, an

auxiliary valve, for said auxiliary mixing conduit.

a suction operated device for operating said auxiliary valve, a conduitfor apply n suction to said suction device, and a valve controlled bysaid manually operated throttle for controlling said suction conduit. a

7. -In an internal combustion enginean intake manifold having aplurality of mixture inlets,

a main mixing conduit connected to one of said inlets and an auxiliarymixing conduit connected to the auxiliary inlet, a manually operatedthrottle valve for said main mixing conduit, a

normally closed auxiliary valve for said auxila iary mixingconduit,means including a device operated by suction developed in said mainmixing conduit for controlling said auxiliary valve, and means dependenton the opening of said manually operated valve for eflecting theoperation of said auxiliary valve.

8. In an internal combustion engine. an intake manifold having aplurality of mixture inlets, a main mixing conduit connected to one ofsaid inlets and an auxiliarymixing conduit connected to the auxiliaryinlet. a manually operated throttle valve for said main mixing conduit,anauxiliary valve for said auxiliary mixing conduit, means controlled bysuction developed.

in said main mixing conduit for controlling said auxiliary valve, aheating device for heating the fuel delivered by said auxiliary mixingconduit,

control means for said heating device, and

means forming an operative connection between said control means andsaid auxiliary valve.

9. In an internal combustion engine, afuel mixtureinlet manifold, fuelmixture forming means, a manually operated throttle valve, a secondbalanced valve for restricting the flow of fuel mixture to saidmanifold, and means in- ,cluding a manually operable member and a.

member operable in accordance with engine suction for controlling saidsecond valve.-

10. In an internal combustion engine having a plurality of cylinders andan intake manifold, a main carburetor for supplying fuel to said intakemanifold, and'means for dampening pulsations from said manifoldcomprisinga second carburetor connected to said manifold at a pointspaced from said main manifold, and means operated by the suctionanterior to the throttle of said main carburetor for opening thethrottle of the second carburetor at high speeds.

11. The method of operating an internal combustion engine including anintake manifold and mixture conduits communicating with said manifold,which comprises arranging the mixtureconduits at such spaced pointsinsaid manifold that the mixture from'one of the conduits will dampenmanifold back pressure pulsations, and automatically controlling theflow mixture passing through one of said mixture conduits by vacuumconditions in the other mixture conduit.

GEORGE B. ERICSON. IRVEN E. COFFEYL

